Liquid crystal display (LCD) panels are one of the essential components of LCDs. Existing TFT LCD panels are widely used in LCD because of its outstanding properties, including low power consumption, small volume, and non-radiation.
Organic light emitting diodes (OLED) unit are organic electroluminescent display devices having outstanding properties such as simple manufacturing process, low manufacturing costs, high light-emitting efficiency, easiness of being flexible, and wide viewing angles, therefore it is a trend to use OLED unit for the display techniques.
As shown in FIG. 1, in a conventional step of etching a source/drain metal layer, a mixing gas 13 including a Cl2 gas and a BCl3 gas is generally used to perform etching of the source/drain metal layer 11. However, once the source/drain metal layer 11 is formed by a physical vapor deposition process, metal on surface of the source/drain metal layer 11 is prone to be oxidized to generate metal oxides 14 due to its contact with air. The metal oxides 14 remain on surface of the source/drain metal layer 11. Thus, during the next step of dry etching of the source/drain metal layer 11 by use of the mixing gas 13 including the Cl2 gas and the BCl3 gas, etching rate of the source/drain metal layer 11 where metal oxides 14 remain would be slow, and etching rate of the source/drain metal layer 11 where metal oxides 14 do not remain would be fast. This not only leads to poor uniformity of source electrode and drain electrode in the source/drain metal layer 11 but influences performance of TFT device.